/*
 * See the dyninst/COPYRIGHT file for copyright information.
 *
 * We provide the Paradyn Tools (below described as "Paradyn")
 * on an AS IS basis, and do not warrant its validity or performance.
 * We reserve the right to update, modify, or discontinue this
 * software at any time.  We shall have no obligation to supply such
 * updates or modifications or any other form of support to you.
 *
 * By your use of Paradyn, you understand and agree that we (or any
 * other person or entity with proprietary rights in Paradyn) are
 * under no obligation to provide either maintenance services,
 * update services, notices of latent defects, or correction of
 * defects for Paradyn.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "elfutils/libdw.h"
#include "Elf_X.h"
#include "dwarfHandle.h"
#include "dwarfFrameParser.h"
#include "debug_common.h"
#include <cstring>

using namespace Dyninst;
using namespace DwarfDyninst;
using namespace std;

// Add definitions that may not be in all elf.h files
#if !defined(EM_K10M)
#define EM_K10M 180
#endif
#if !defined(EM_L10M)
#define EM_L10M 181
#endif
#if !defined(EM_AARCH64)
#define EM_AARCH64 183
#endif

/*void DwarfHandle::defaultDwarfError(Dwarf_Error err, Dwarf_Ptr p) {
  dwarf_dealloc(*(Dwarf*)(p), err, DW_DLA_ERROR);
  }

  Dwarf_Handler DwarfHandle::defaultErrFunc = DwarfHandle::defaultDwarfError;*/

DwarfHandle::DwarfHandle(string filename_, Elf_X *file_,
        void * /*Dwarf_Handler err_func_*/) :
    init_dwarf_status(dwarf_status_uninitialized),
    dbg_file_data(NULL),
    file_data(NULL),
    line_data(NULL),
    type_data(NULL),
    frame_data(NULL),
    file(file_),
    dbg_file(NULL),
    //err_func(err_func_),
    filename(filename_)
{

    locate_dbg_file();
}

void DwarfHandle::locate_dbg_file()
{
    char *buffer;
    unsigned long buffer_size;
    bool result = file->findDebugFile(filename, debug_filename, buffer, buffer_size);
    if (!result)
        return;
    dbg_file = Elf_X::newElf_X(buffer, buffer_size, debug_filename);
    if (!dbg_file->isValid()) {
        dwarf_printf("Invalid ELF file for debug info: %s\n", debug_filename.c_str());
        dbg_file->end();
        dbg_file = NULL;
    }
}

bool DwarfHandle::init_dbg()
{
    //int status;
    //Dwarf_Error err;
    if (init_dwarf_status == dwarf_status_ok) {
        return true;
    }

    if (init_dwarf_status == dwarf_status_error) {
        return false;
    }

    file_data = dwarf_begin_elf(file->e_elfp(), DWARF_C_READ, NULL);

    //if (!file_data /*&& errno==0*/ )  {
    //    init_dwarf_status = dwarf_status_error;
    //    return false;


    if (dbg_file) {
        dbg_file_data = dwarf_begin_elf(dbg_file->e_elfp(), DWARF_C_READ, NULL); 
        //status = dwarf_elf_init(dbg_file->e_elfp(), DW_DLC_READ,
        //        err_func, &dbg_file_data, &dbg_file_data, &err);

        if (!dbg_file_data) {
            init_dwarf_status = dwarf_status_error;
            return false;
        }

        //Have(sic) a debug file, choose which file to use for different lookups.
        line_data = &dbg_file_data;
        type_data = &dbg_file_data;

        if (hasFrameData(dbg_file))
            frame_data = &dbg_file_data;
        else
            // file_data might also not have frame data
            frame_data = &file_data;
    }
    else {
        //No debug file, take everything from file
        line_data = &file_data;
        type_data = &file_data;
        frame_data = &file_data;
    }

    Dyninst::Architecture arch;
    switch (file->e_machine()) {
        case EM_386:
            arch = Arch_x86;
            break;
        case EM_X86_64:
        case EM_K10M:
        case EM_L10M:
            arch = Arch_x86_64;
            break;
        case EM_PPC:
            arch = Arch_ppc32;
            break;
        case EM_PPC64:
            arch = Arch_ppc64;
            break;
        case EM_ARM:
            arch = Arch_aarch32;
            break;
        case EM_AARCH64:
            arch = Arch_aarch64;
            break;
        case EM_CUDA:
            arch = Arch_cuda;
            break;
        default:
            assert(0 && "Unsupported archiecture in ELF file.");
            return false;
    }

    // .eh_frame might be in file->e_elfp(), cause it's not stripped
    sw = DwarfDyninst::DwarfFrameParser::create(*frame_data, file->e_elfp(), arch);

    // if file is stripped and there's no dbg_file we still make dwarf_status_ok.
    // That's why who uses line_dbg(), type_dbg(), and frame_dbg() have to
    // check if the returned pointer is not null.
    init_dwarf_status = dwarf_status_ok;
    return true;
}

const char* frame_section_names[] = { ".debug_frame", ".eh_frame", NULL };
bool DwarfHandle::hasFrameData(Elf_X *e)
{
    unsigned short shstrtab_idx = e->e_shstrndx();
    Elf_X_Shdr &shstrtab = e->get_shdr(shstrtab_idx);
    if (!shstrtab.isValid())
        return false;
    Elf_X_Data data = shstrtab.get_data();
    if (!data.isValid())
        return false;
    const char *shnames = data.get_string();

    unsigned short num_sections = e->e_shnum();
    for (unsigned i = 0; i < num_sections; i++) {
        Elf_X_Shdr &shdr = e->get_shdr(i);
        if (!shdr.isValid())
            continue;
        if (shdr.sh_type() == SHT_NOBITS)
            continue;
        unsigned long name_idx = shdr.sh_name();
        for (const char **s = frame_section_names; *s; s++) {
            if (strcmp(*s, shnames + name_idx) == 0) {
                return true;
            }
        }
    }
    return false;
}

Elf_X *DwarfHandle::origFile()
{
    return file;
}

Elf_X *DwarfHandle::debugLinkFile()
{
    return dbg_file;
}

Dwarf **DwarfHandle::line_dbg()
{
    if (!init_dbg())
        return NULL;
    return line_data;
}

Dwarf **DwarfHandle::type_dbg()
{
    if (!init_dbg())
        return NULL;
    return type_data;
}

Dwarf **DwarfHandle::frame_dbg()
{
    if (!init_dbg())
        return NULL;
    return frame_data;
}


DwarfHandle::~DwarfHandle()
{
    if (init_dwarf_status != dwarf_status_ok)
        return;

    //Dwarf_Error err;
    if (dbg_file_data)
        dwarf_end(dbg_file_data);
    if (file_data)
        dwarf_end(file_data);
}

map<string, DwarfHandle::ptr> DwarfHandle::all_dwarf_handles;
DwarfHandle::ptr DwarfHandle::createDwarfHandle(string filename_, Elf_X *file_,
        void* /*Dwarf_Handler err_func_*/)
{
    map<string, DwarfHandle::ptr>::iterator i;
    i = all_dwarf_handles.find(filename_);
    if (i != all_dwarf_handles.end()) {
        return i->second;
    }

    DwarfHandle::ptr ret = DwarfHandle::ptr(
            new DwarfHandle(filename_, file_, NULL /* err_func_*/));
    all_dwarf_handles.insert(make_pair(filename_, ret));
    return ret;
}

DwarfFrameParserPtr DwarfHandle::frameParser() {
    return sw;
}
